The women were possibly duped by a spy ring into attacking Kim Jong-un's half brother.

Bangkok/Jakarta: An Indonesian woman arrested over the assassination of North Korean leader Kim Jong-un's half-brother, were duped into believing she was taking part in a television show prank, according to police.

The revelation came as police raided an apartment in Kuala Lumpur and arrested a 47-year-old man holding a North Korean passport.

Police said in a statement Ri Jong-chol, born in 1970, was arrested on Friday night in Selangor state. He is the fourth suspect to be arrested in the investigations surrounding the 46-year-old's death at Kuala Lumpur International Airport on Monday.

Indonesia's police chief Tito Karnavian said Indonesia had received information from Malaysia the woman, Siti Aisyah, was "just being used" and didn't realise it was an assassination attempt by foreign agents.

He said Ms Siti, 25, from Serang in Indonesia's Banten province, had been paid to participate in a comedy show. She was tricked into thinking she was taking part in Just for Laughs, a popular hidden camera series.

"So one of the females covers the eyes and the other one sprays something," he told reporters in Aceh. "They have done it three to four times [before]. She was given a few dollars for the action."

However he said it was suspected the spray used in the "prank" against Mr Kim contained a dangerous substance.

Malaysian police say Ms Siti and 29-year-old Vietnamese Doan Thi Huong were captured by CCTV cameras at Kuala Lumpur International Airport at the time that Mr Kim was poisoned on Monday. Mr Kim became unwell and died in an ambulance on way to a hospital after telling staff at an airport clinic he'd been poisoned.

Both women and a man police said was Ms Siti's boyfriend have been remanded in custody for a week, pending further investigations.

Ms Siti's mother told Fairfax Media she is a "simple country girl" who had been working in a clothing shop in Batam, an Indonesian island near Singapore.

Indonesian officials say immigration records show her last departure from Indonesia was on February 2 when she travelled from Batam to Johor, a state in southern Malaysia.

Ms Siti's nephew, Iqbal, who goes by just one name, said Ms Siti had also been involved in filmed pranks in Jakarta.

Mr Iqbal said Ms Siti received about 2 to 3 million rupiah ($200 to $300) for each filmed prank, which he added never appeared on TV in Indonesia.

He was quoted in news wire detik.com saying the producer had not allowed her to watch the filmed pranks.

"The producer said: 'Why would you watch it? If you watch it, then it would be useless'," Mr Iqbal said.

Indonesian Vice President Jusuf Kalla has also said Ms Siti had been a victim of some kind of trickery. Detik.com reported he did not believe Ms Siti was a North Korean agent because she stayed in Malaysia and did not escape.

As of Friday night, the Directorate General of Immigration was yet to verify that the passport in the name of Siti Aisyah seized by Malaysian authorities was a real Indonesian passport or if the woman arrested was indeed Ms Siti.

Ms Siti's former father-in-law, Tjia Liang Kiong, also scoffed at suggestions that Ms Siti was an agent.

"I just laughed ... how can she be an agent? She doesn't speak any English and her highest level of education is only junior high school," Mr Kiong told reporters from his home in Tambora, West Jakarta.

Diplomatic spat

In the latest twist to the bizarre killing, a diplomatic row has broken out between North Korea and Malaysia over Mr Kim's body.

In his first public comments on the assassination, North Korea's ambassador in Kuala Lumpur Kang Chol said his country would "categorically reject" Malaysia's autopsy report and demanded the body be released to North Korean officials immediately.

"The Malaysian side forced the post-mortem without our permission or witnessing," Mr Kang told reporters outside a hospital.

Mr Kang said North Korea rejected a post-mortem "because he is a diplomatic passport holder who is under consular protection of the DPRK (North Korea).

He made no reference to Mr Kim by name.

Malaysia's police chief Khalid Abu Bakar told reporters that rules and procedures must be followed in the case. Malaysia has said the body would not be released until it receives DNA samples from Mr Kim's next of kin.

Results of forensic tests have not been made public.

On Saturday, a senior Malaysian official said a second autopsy will be carried out on Mr Kim's body because the first one was inconclusive. The autopsy was expected to be carried out late Saturday.

South Korea has pointed the finger of blame at North Korea, citing a "standing order" from North Korea's leader.

Celebrations in Pyongyang to mark the birthday of Kim Jong-il, the men's late father, have gone ahead without reference to the death.

Yoji Gomi, a Tokyo-based journalist who wrote a book about Kim Jong-nam, told Associated Press that he opposed his family's rule of the pariah state and wanted economic reforms.

Mr Gomi said Kim Jong-nam appeared nervous when he interviewed him in 2011.

"He must have been aware of the danger, but I believe he still wanted to convey his views to Pyongyang via the media," he said.

"He was sweating all over his body and seemed uncomfortable when he responded to my questions ... he was probably worried about the impact of his comments and expressions," he said.

"The thought now gives me a pain in my heart."

North Korean spies have a long history of assassinations and kidnappings in foreign countries.

One 14-year-old Japanese girl was kidnapped to teach Japanese to North Koran spies.

In October 2012, South Korean prosecutors said a North Korean man detained as a spy had admitted involvement in a plot to stage a hit-and-run accident targeting Kim Jong-nam in China in 2010.

The country's Reconnaissance General Bureau (RGB) has had agents infiltrate Malaysia, Singapore and Indonesia for decades, according to Malaysian intelligence officials quoted by The Star Asia News Network. Agents disguise themselves working in jobs like the construction industry and run restaurants, it said.

Malaysia is one of a dwindling number of countries that have close relations with North Korea, which is under global sanctions over its missile launches.

Indonesia's vice-president Jusuf Kalla, told reporters on Friday he was confident Siti was not a North Korean agent, saying if she was she would have disappeared by now.

Police arrested Ms Siti in a Kuala Lumpur hotel early Thursday after being led there by her 26-year-old Malaysian boyfriend.

"Why would she go and stay in a hotel in the same city, so close to the airport," Mr Jusuf was reported as saying by Detik.com.

On Monday at the airport one woman stood in front of Mr Kim to distract him while another came from behind and dabbed a handkerchief believed to contain poison in his face.

Images of the women were captured on CCTV cameras.

Mr Kim became unwell and died in an ambulance on the way to a hospital.

Malaysian police are hunting four men believed to be North Korean spies who they believe orchestrated the assassination.

They believe the men are still in Malaysia and authorities have increased security at border exit points.